(i) Technical Field
A certain aspect of the embodiments discussed herein is related to a method for tuning a semiconductor laser.
(ii) Related Art
A wavelength tunable laser disclosed in Japanese Patent Application Publication No. 2007-48988 has a SG-DBR (Sampled Grating Distributed Bragg Reflector) region having a plurality of wavelength selection portions. A heater controls a temperature of each wavelength selection portion. Thus, wavelength selection characteristics are controlled with refraction index changing.
In the wavelength tunable laser, a reflection spectrum wavelength selected through overlapping of wavelength characteristics of each wavelength selection portion of the SG-DBR region and a gain spectrum wavelength of a SG-DFB (Sampled Grating Distributed Feedback) region are made to correspond to each other, and an oscillation wavelength is fixed to a predetermined wavelength.